1. Field of the Invention
The present invention relates in general to a protective device and, more particularly, to an impact absorbing liner for use in a protective helmet to, in turn, provide impact management over an extended period of time.
2. Background Art
Protective helmets have been know in the art for many years. In particular, many of these protective helmets are constructed of multiple layers of impact absorbing material. Likewise, protective helmets fabricated from materials with different impact absorbing characteristics are also know in the art. These helmets provide both increased comfort for the helmet wearer and increased ability of the helmet to absorb different impacts.
For instance, both Johnson, U.S. Pat. No. 3,946,441, and Marker, U.S. Pat. No. 4,006,496 show a safety helmet with a hard outer shell, and a shock-absorbing inner shell made of two different materials. The different materials each appear to have different impact absorbing properties, for performance during a range of different impact loads. The helmets also have a fitting pad to encircle the wearer's head for increased fit and comfort. Likewise, Mitchell et al., in U.S. Pat. No.'s 4,534,068 and 4,558,470, appear to disclose a shock attenuation system for use with protective headgear wherein on outer shell is lined with a shock absorbing layer, a layer of flexible slow recovery foam, and a layer of rapid recovery foam.
Moreover, Garneau, in U.S. Pat. No. 5,351,342, appears to disclose a safety helmet which comprises of a hard outer shell, a shock absorbing insert for contact with the wearer's head, and a hard inner shell embedded in the shock absorbing insert for additional impact protection. The hard inner shell has fingers which project through the inner face of the shock absorbing insert so as to come flush with the inner face of the insert, to better anchor the hard inner shell within the insert. Finally, both Morgan, U.S. Pat. No. 5,669,079, and Broersma, U.S. Pat. No. 5,309,576, appear to disclose a protective helmet with a hard outer shell, an impact absorbing liner, and a material with separate impact absorbing characteristics imbedded or inserted into the liner material.
Although these and other conventional helmet liners have worked well, they have failed to provide protection against both high and low degrees of impact imparted on a helmet, over the extended life of a helmet. Moreover, it is always a goal in the art to increase the impact absorption and dissipation capabilities of protective helmets.